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Factors Affecting Rates of Reaction
Thanks to Michelle Craig
Manitoba Curriculum
Chemistry Grade 12; Kinetics, Topic 3-05
Objectives
To design short experiments to investigate the individual affects of temperature,
concentration, catalyst, and surface area on the rate of chemical reactions.
Apparatus and Materials Available
3 x 250 mL beakers
3 x test tubes
test tube rack
10 mL graduated cylinder
3 x Alka Seltzer® tablets
0.1 M hydrochloric acid, HCl
1.0 M hydrochloric acid, HCl
6.0 M hydrochloric acid, HCl
pieces of zinc (1 cm x 1 cm)
magnesium ribbon (1 cm)
magnesium powder
mossy zinc
copper turnings
copper(II) sulfate
hot bath
ice bath
steel wool
thermometer
*additional materials may be made available upon request*
Part 1: Affect of Temperature
Designing an Experiment
A) Design a simple experiment using the reaction of Alka Seltzer® with water that will
qualitatively investigate the affect of temperature on the rate of reaction. You may
use any of the materials listed above in your investigation. Keep in mind that, in any
experiment where you want to determine the affect of one variable, you should attempt
to keep all other variables constant.
Write out the steps to your procedure in point form. Be sure to include the details of
what variables are remaining unchanged between trials and which is being altered.
B) Design a data table to record your results and observations.
Hypothesis
State your hypothesis before carrying out your procedure.
Procedure
Carry out the steps of the experiment that you designed, recording the results and
observations in the data table that you designed.
Conclusions
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a) Write a statement that is one or two sentences long to summarize your findings
regarding the affect of temperature on the rate of reaction.
b) Look on the side of the Alka Seltzer® bottle to determine the main ingredient in the
tablet and write the balanced chemical equation for the reaction that you observed.
c) Considering what you’ve learned about Collision Theory in class, explain how
changing the temperate of a reaction will affect the reaction rate.
d) Put on your “particulate glasses” and take a look into each of your reactant vessels.
Draw two pictures, one of the reactants at a low temperature, and the second of the
reactants at a higher temperature. Explain in a caption box below each picture what is
happening to the particles involved that is causing the observed change in reaction rate.
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e) Give an example from your own experience where the affect of temperature on the
rate of a chemical reaction has (or could) impact your life. Eg) Hypothermia
OR create an analogy for the affect of temperature on the rate of reaction.
Part 2: Affect of Concentration
Designing an Experiment
A) Design a simple experiment using the reaction of zinc with hydrochloric acid that will
qualitatively investigate the affect of concentration of the reactants on the rate of
reaction. You may use any of the materials listed above in your investigation. Write out
the steps to your procedure in point form. Be sure to include the details of what
variables are remaining unchanged between trials and which is being altered.
B) Design a data table to record your results and observations.
Hypothesis
State your hypothesis before carrying out your procedure.
Procedure
Carry out the steps of the experiment that you designed, recording the results and
observations in the data table that you designed.
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Conclusions
a) Write a statement that is one or two sentences long to summarize your findings
regarding the affect of concentration on the rate of reaction.
b) Write the balanced chemical equation for the reaction that you observed.
c) Considering what you’ve learned about Collision Theory in class, explain how
changing the concentration of the reactants will affect the reaction rate.
d) Put on your “particulate glasses” and take a look into each of your reactant vessels.
Draw two pictures, one with the reactants at a low concentration, and the second of the
reactants at a higher concentration. Explain in a caption box below each picture what is
happening to the particles involved that is causing the observed change in reaction rate.
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e) Give an example from your own experience where the affect of concentration on the
rate of a chemical reaction has (or could) impact your life.
OR create an analogy for the affect of temperature on the rate of reaction.
Eg) As the number of students in the hallways increase (i.e. during breaks) the number
of collisions that occurs between the students increases.
Part 3: Affect of Surface Area
Designing an Experiment
A) Design a simple experiment using the reaction of magnesium ribbon and magnesium
powder with hydrochloric acid that will qualitatively investigate the affect of surface
area of the reactants on the rate of reaction. You may use any of the materials listed
above in your investigation. Write out the steps to your procedure in point form. Be
sure to include the details of what variables are remaining unchanged between trials
and which is being altered.
B) Design a data table to record your results and observations.
Hypothesis
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State your hypothesis before carrying out your procedure.
Procedure
Carry out the steps of the experiment that you designed, recording the results and
observations in the data table that you designed.
Conclusions
a) Write a statement that is one or two sentences long to summarize your findings
regarding the affect of surface area of the reactants on the rate of reaction.
b) Write the balanced chemical equation for the reaction that you observed.
c) Considering what you’ve learned about Collision Theory in class, explain how
changing the surface area of the reactants will affect the reaction rate.
d) Put on your “particulate glasses” and take a look into each of your reactant vessels.
Draw two pictures, one with the reactants with a small surface area, and the second of
the reactants at a larger surface area. Explain in a caption box below each picture what
is happening to the particles involved that is causing the observed change in reaction
rate.
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e) Give an example from your own experience where the affect of surface on the rate of
a chemical reaction has (or could) impact your life. Eg) Dissolving a clump of sugar in
coffee versus dissolving granular sugar in coffee.
OR create an analogy for the affect of surface area on the rate of reaction.
Part 4: Affect of a Catalyst
Designing an Experiment
A) Design a simple experiment to determine if either copper turnings or copper (II)
sulfate act as a catalyst in the reaction of zinc with hydrochloric acid. You may use any
of the materials listed above in your investigation. Write out the steps to your
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procedure in point form. Be sure to include the details of what variables are remaining
unchanged between trials and which is being altered.
B) Design a data table to record your results and observations.
Hypothesis
State your hypothesis before carrying out your procedure.
Procedure
Carry out the steps of the experiment that you designed, recording the results and
observations in the data table that you designed.
Conclusions
a) Write a statement that is one or two sentences long to summarize your findings.
b) Write the balanced chemical equation for the reactions that you observed.
c) Explain why you would or would not consider copper (II) sulfate and copper turnings
to be catalysts.
d) Put on your “particulate glasses” and take a look into each of your reactant vessels.
Draw two pictures, one with reaction with copper turnings, and the second of the
reaction with copper (II) sulfate. Explain in a caption box below each picture what is
happening to the particles involved that is causing the observed change in reaction rate.
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e) Give an example from your own experience where the affect of a catalyst on a
chemical reaction has (or could) impact your life. Eg) the enzymes (biological catalysts)
involved in digestion of the food you eat.
OR create an analogy for the affect of a catalyst on the rate of reaction.
Reference:
Modified from:
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Frankel, A. & Li, J. (1989) Chemistry: a second course. Don Mills, Ontario: AddisonWestley Publishers. (pp. 34-36)